The government knows that these positions are irreconcilable. Natural gas is mainly used for producing electricity. The draft energy bill, launched last week, says that if the government's legal obligation to cut 80% of greenhouse gases by 2050 is to be met, electricity plants "need to be largely decarbonised by the 2030s". (This is a subtle slippage from December's Carbon Plan, which said 2030). The only hope of reconciliation lies in the universal deployment of carbon capture and storage: technology which removes the carbon dioxide emanating from power stations and buries it. But the government has made it clear that it does not believe this is going to happen.

The new bill sets a limit for the amount of carbon dioxide that power stations can produce. This is 450 grams of CO2 for every kilowatt-hour of electricity. Compare it to the 50g which the Committee on Climate Change says should be the average produced by power stations in this country by the end of the 2020s, if the government is to meet its 2050 target.

Modern gas power stations produce less than 400g/kWh, so the new limit won't touch them. Worse, the level will be fixed – by primary legislation – until 2045 for power stations built today: in 33 years gas plants will still be allowed to produce more CO2 than they do at the moment. If the government believed that widespread carbon capture and storage (CCS) was a realistic prospect, it would ratchet down the emissions from gas plants, forcing them to use the technology. But CCS of this kind has not yet been proven at scale, and is now beset with major problems. The government's plans for cutting our contribution to global warming rely on vapourware .

As the energy secretary said in March: "I want a decarbonised grid in the long term, but we can't take our foot off the gas for some time yet." In this bill we see the rupture of the cross-party consensus on climate change, and the abandonment of the carbon budgets required to meet the 2050 target.

But at least the government's emissions limit will prevent new coal plants being built without CCS. Won't it? New plants produce about 800g/kWh, so they appear to be excluded by the 450g limit. This would be consistent with the promise in the coalition agreement: the rules "will prevent coal-fired power stations being built unless they are equipped with sufficient carbon capture and storage to meet the emissions performance standard". But this promise has just been reclassified as biomass, and used to ignite David Cameron's pants.

The draft bill explains that any new coal plant that "forms part of" the capture and storage programme will be exempted from the emissions standard. What it does not say is that a single gram of CO2 needs to be captured from the plant in question. The bill makes this explicit. It defines a power station in the capture and storage programme as one in which CCS "is or is to be … used in commercial electricity generation". To qualify under the bill, a coal plant would need only to plan on fitting, one day not very soon, some CCS capacity, the quantity of which is not specified. As well as the coalition agreement, this rips up the commitments in both last year's white paper and the national policy statement.

So a putative green technology is being used as a means of absolving new coal plants from the need to reduce greenhouse gases. Through a series of subtle prestidigitations, both coal and gas plants have been exempted from any targets for cutting carbon emissions: and with that the 2008 Climate Change Act goes up in smoke.

Throughout this inferno of a bill there is not a single new commitment to energy efficiency. It relies only on the government's green deal. But this will reduce the number of installations of cavity wall insulation from the 800,000 envisaged this year under the last government's programme to 100,000. The government's own figures show that almost the same number would have been insulated with no programme at all. In his first speech as secretary of state, Ed Davey insisted that energy efficiency "has to be right at the heart of what we do". But in his new bill it's not even on the periphery. Its absence ensures a guaranteed market for the unabated gas and coal plants the government intends to approve.

Promises, targets, legal obligations, the act which was supposed to guarantee our carbon cuts: all are to be vaporised in the power station furnaces. This is a government of the old and the dirty, committed to the technologies of a previous century, without a wisp of concern for the future.